DIRECTIONAL CHANGES IN TISSUE REFLECTIVITY MAY INFLUENCE FLOW DETECTION ON OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY

Purpose: To determine if directional or anatomical changes in tissue reflectivity of Henle fiber layer (HFL) may influence flow detection on optical coherence tomography angiography (OCT-A). Methods: Cross-sectional analysis of consecutive cases undergoing OCT-A. Directional changes in visualization of HFL were either produced manually by moving the beam entrance within the pupil or observed occurring naturally because of tilting of the OCT linescan within a myopic staphyloma. Areas of enhanced HFL visualization were identified on cross-sectional and en face structural OCT scans. Visualization of OCT-A flow within the superficial and the deep capillary plexuses were compared in areas with and without enhanced HFL reflectivity. Results: Fifteen eyes from 9 patients were included, with a mean age of 49.6 +/- 17.9 years. On OCT-A, retinal areas with enhanced HFL reflectivity produced manually or by scan tilting within myopic staphylomas showed no changes in the superficial capillary plexus flow. However, deep capillary plexus flow was altered by variable projection of the superficial flow onto the deeper retinal layers. Conclusion: Directional changes in HFL reflectivity can alter the detection of deep capillary plexus flow imaged with OCT-A by influencing the projection of superficial flow onto the deeper retinal layers. We recommend that clinicians minimize scan tilting during scan acquisition and be aware of this phenomenon in eyes with posterior staphyloma.